Hello,
I was hoping to hear your opinion about a serious problem I have - it is either I solve it or reduce my LPC2478 CPU speed from 72[MHz] to 64[MHz] (11% loss. The problem does not seem to be occurring at lower MHz settings). I posted about this in the past but it was a long time ago. When I place a controller in an environmental chamber and increase the temperature to 80+ Celsius degrees, I often see data abort exceptions, and sometimes I get the impression that the PC takes a hike (even the firmware LED that blinks every 1 second becomes irregular for a while before it stops). The program is launched by a boot loader and has a lower level supporting firmware layer that handles some interrupts (not all). I also see that if RTX is not started at all (but the application hangs in a "for (;;)" loop instead, hence the bootloader and firmware layer were/are involved, but the application is idle) - the system never crashes! I have excluded, as far as I could tell, the roll of external memory or RTX in this situation. However, I still suspect RTX a little (even though my test programs never crashed). My question: did you ever encounter such a situation? Where do I look best? can this be the result of a misbehaving peripheral? NXP have confirmed the LPC2478 is not the reason.
NXP have confirmed the LPC2478 is not the reason.
Odd ... the maximum allowed ambient temperature for the commercial version of the chip is 85 degrees Celsius. "80+ degrees" sounds awfully close to that.
Besides the CPU, there are a few other possible suspects, like the power supply. I wouldn't exclude the external memory until after a thorough examination - at 80 °C the external memory interface of the chip might be operating close to its worst-case specs. Another candidate for investigation is the flash memory of the chip (if it is used).